Assembly Of Low Dimensional Carbon-based Nanostructures Toward Performance Study

Due to the uniquely mechanical,electrical,optical and thermal properties of carbon-based nanomaterials,they have been applied in the sensors,catalysis and renewable green energy fields.The functional modification and controllable assembly of the low dimentional carbon-based nanostructures open up opportunities to construct materials for energy conversion and storage.In this work,chemically exfoliating method was used to obtain zero dimentional oxygen functional graphene quantum dots,one dimentional oxygen functional grephene nanoribbons and two dimentional oxygen functional graphite carbon nitride nanosheets.The oxygen-functionalization for the carbon-based nanomaterials can contribute them to disperse in water uniformly,setting the basis for the subsequently aimed assembly.Based on the above materials,platinum-copper alloy nanoparticles-graphene quantum dots hybrid capsules,stratiform voile-like oxygen functional graphene nanoribbons aerogel and cuprous oxide-graphite carbon nitrogen core-shell nanowires were prepared,which can be used in energy transformation and sensor field,respectively.1)Zero dimentional oxygen functional graphene quantum dotsThe unique platinum-copper alloy nanoparticles-graphene quantum dots hybrid capsules have been prepared by a dually spontaneous reduction and assembly process of oxygen functional graphene quantum dots and platinum precursor???by galvanic displacement reaction on copper microspheres.The inner platinum-copper alloy shell layer was assembled with stacked platinum-copper nanoparticles,inducing plenty of porosity defects,which can act as the catalytic centers to interact with oxygen molecules;The outer graphene quantum dots shell layer rich of edge flaws can manipulate the binding of reaction intermediates on the catalytic surface,contributing the catalytic activity.Based on the unique hybrid structure,platinum-copper alloy nanoparticles-graphene quantum dots hybrid capsules showed remarkably enhanced catalytic activity for oxygen reduction reaction with a 2 times higher mass activity and a 40 mV more positive onset potential than that of commercial Pt black,indicating the promise of the newly-prepared platinum-copper alloy nanoparticles-graphene quantum dots hybrid capsules as catalysts for fuel cell applications.2)One dimentional oxygen functional graphene nanoribbonsThe large-scale assembly of oxygen functional graphene nanoribbons has been realized by the simple freeze casting method.The unique stratiform voile-like oxygen functional graphene nanoribbons aerogel has been prepared by adjusting the initial solution concentration for freezing,during which reticular seaweed-like oxygen functional graphene nanoribbons aerogels and dense stacked stromatolite-like oxygen functional graphene nanoribbons aerogels have also been obtained.The layer-by-layer arranged network structure of stratiform voile-like oxygen functional graphene nanoribbons aerogel constructed plenty of pore channels,contributing the imitate interaction of the oxygen-containing groups on the surface of oxygen functional graphene nanoribbons with the water molecules and causing the high water absorption content,meanwhile,ensuring the necessarily mechanical property of the functional devices.Under the moisture-electricity annealing process,the gradient stratiform voile-like oxygen functional graphene nanoribbons aerogel has been prepared,which can provide 40 mV voltage and120 mW m^-2 power density under moisture.Compared with the self-power property of the other aerogels which have only the reticular or stratiform structure,confirming the microstructure of the aerogel has key roles on the device property,which can set the light on constructing noval carbon-based nanomaterials for energy transformation.3)Two dimentional oxygen functional graphite carbon nitrideBased on the experience that oxygen functional graphene quantum dots can be induced to subsequently reduct and assemble on the surface of active metals at room temperature,we further verified oxygen functional graphite carbon nitride can also been spontaneously reducted and assembled on the surface of the active metal copper.The unique cuprous oxide-graphite carbon nitrogen core-shell nanowires with highly hierarchical sharp edges on the surface has been prepared based on oxygen functional graphite carbon nitride.Combined with the hybrid effect of cuprous oxide with graphite carbon nitrogen,such hierarchical cuprous oxide-graphite carbon nitrogen core-shell nanowires possess the sensitivity to humidity and photocurrent response.